Failure to recognize that many laboratory animals live unhealthy lives may be leading researchers to misinterpret their findings, according to Nature News. Writing in PNAS, researchers at the National Institute on Aging discuss that many laboratory mice and rats are metabolically morbid, and, consequently, will die sooner than animals of normal weight. “The most logical way to extrapolate is to say any data we obtain in the animal model would be more relevant to overweight, sedentary humans than normal-weight, active individuals,” Mark Mattson, a co-author on the paper, told Nature News. The NIA team suggests that researchers not allow their animals constant access to food, but rather feed them every other day and include an exercise wheel in their cages. The team also suggests that murine-based studies which conclude that caloric restriction increases lifespan be reconsidered, given that many animals are scored against an unhealthy baseline.
On that same theme, a study in Cell Metabolism from researchers at the University of Alberta have found that decreasing the activity of triacylglycerol hydrolase in mice lowers the amount of fat in the blood and improves glucose metabolism. It also appears to keep fat out of organs that weren't meant to store it, such as the liver, and protects the pancreas's insulin-producing beta cells. Mice lacking the TGH enzyme also burned more fat and were more physically active than those with the enzyme. The researchers hope that TGH could be a target for drugs to combat obesity, and its metabolic complications such as diabetes.